A track-type tractor comprises a pair of endless tracks mounted on either side thereof to propel the tractor during construction operations. Each track assembly is normally driven by a sprocket rotatably mounted on the frame of the tractor and driven by a final drive enclosed by a housing also secured to the frame. During certain conditions of tractor operation, dirt and other debris tend to impact between the track assembly and the housing to thus increase the tractive effort of the tractor and to cause undue wear thereat.